Double Earthquake Fears Loom in Bay Area

David Moir / Reuters
David Moir / Reuters

California scientists have recently begun speaking of a nightmare double earthquake scenario where the Hayward and Calaveras faults would trigger each other to make for a combined shaker that would devastate the Golden State. The estimated costs in damages are approximately $300 billion.

An article and accompanying geometric model published by UC Berkeley seismologist Estelle Chaussard in the journal Geophysical Research Letters outlines this possibility. According to KQED, deep beneath the earth’s surface the two fault lines combine, and scientists suggest that an end-to-end rupture of the Hayward fault would result in a 7.5 magnitude quake in and of itself. That, combined with a spillover and activation of the Calaveras fault, would create a “mega fault” and result in roughly the same type of disaster that destroyed over 80% of San Francisco in 1906: a 7.8 magnitude earthquake that cost over 3,000 lives that fateful year. The effects of such a combined shaker would be far more harrowing, however.

Since 1900, California’s population has grown by nearly 4o times, making it the most populous state in the union. Although the report did not provide figures of how many lives would be lost, one need only compare numbers to arrive at his/her own conclusion.

In her paper, Chaussard outlines a creep where both faults extend by several millimeters per year–something for which both faults are known.

“We hope our paper will trigger the necessary interest so that other groups start working on it,” Chaussard told KQED. Her new model of the Hayward-Calaveras juncture will hopefully help scientists run realistic earthquake simulations that could potentially aid them in planning for the dangers that lie ahead if and when such a doomsday scenario strikes.

Follow Adelle Nazarian on Twitter @AdelleNaz.


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